Question

A carbonyl compound X(C$_5$H$_8$O) gives yellow precipitate with NaOI. Hemiacetal of X with methanol/dry HCl is:

• A.

  

• B.

  

• C.

  

• D.

  

Hint:

A compound giving yellow ppt with NaOI has CH$_3$CO– group and forms hemiacetals with alcohols.

Answer 1

The Correct Option is C

Positive iodoform test (yellow ppt with NaOI) indicates presence of CH$_3$CO– group.
Hemiacetal formation with CH$_3$OH gives a structure having both –OH and –OCH$_3$ on same carbon.
Only structure (3) matches CH$_3$–C(OH)(OCH$_3$)–C$_6$H$_5$.